This invention relates generally to electrical connectors, and more particularly, to test fixtures for electrical connectors.
Modern electronics use test fixtures to test high frequency and high speed electrical connectors. Conventional test fixtures typically include printed circuit boards that are electrically coupled to the electrical connectors. Due to continuing trends toward miniaturization, test fixtures typically utilize surface mount technology to accommodate the high density of contacts on today's electrical connectors. With surface mounting, signal contacts located on the printed circuit board can be closely spaced, thereby allowing more contacts to be mounted in the same area of the board. As such, signal contacts are placed in close proximity to one another, thereby leading to the potential for cross talk between neighboring signal contacts. Signal conductor pads, or contact fingers, located on the electrical connector, are coupled to the test fixture signal contacts and transmit data across the test fixture circuit boards along traces extending from the signal contacts.
Today, many connectors carry signals arranged in differential pairs. Hence, the test fixtures are configured to test operation of such connectors while conveying differential pairs. Known test fixtures include shielding or ground pads between traces associated with adjacent differential pairs to reduce cross talk therebetween. However, once the traces extend beyond the ground pads, an area exists in which a large amount of cross talk is created due to the close spacing and large number of traces. Thus, certain problems remain in connection with ensuring and measuring the signal integrity and the accuracy of test measurements.